I am not a lawyer. The people on this website probably aren't either. But in general, it seems any use of a patented invention is infringement of the patent.
I'm sure that for personal use with no commercial gain, that copying a patented design and not giving or selling it out is never going to be noticed or prosecuted. (It costs money to defend a patent).
If you build a patented invention that you then use to manufacture and sell profitable goods, you are again infringing and the patent holder will have monetary damages (your profits) to pursue.